“If something is comforting, that’s great, but it doesn’t make it true,” says Dawkins, arguably the world’s most famous atheist. “There are people who sincerely seem to think that because something is consoling or comforting that therefore it’s got to be true. That just isn’t logical.”

Appearing on Global’s The Morning Show, Dawkins quoted Canadian experimental psychologist Steven Pinker. “[He] said, ‘If you’re being chased by a tiger, it may comfort you to believe it’s a rabbit. But it is a tiger and it’s going to eat you.'”

Krauss, who was raised in Toronto, said the goal is not to make people feel bad about believing in God.

“We recognize that all of us need comfort in different ways,” he explains. “What we’re just trying to encourage people to do is get comfort from the real world.

“We’re not trying to take something away. We’re trying to add the wonder of reality, the poetry of the real universe, and say ‘you can get solace and wonder from the real world.’ It’s true, you can get comfort from religion but that doesn’t say you have to have religion to get comfort.”

He points out the universe does not exist so people can be happy. “We have to understand reality and if we get comfort from things that are imaginary, well, it helps us in the short run but in the long run it leads us to act in often irrational ways.”

Dawkins admits challenging religious beliefs makes some people very upset.

“Religious people do get extremely emotional. If you criticize their religion it’s almost as though you say they’ve got an ugly face or something,” he says. “All we’re doing is criticizing a view of the world which they hold and asking for the evidence, or criticizing the evidence.”

Dawkins hopes The Unbelievers will spark more debate and, perhaps, open a few minds.

“Science is wonderful, truth is wonderful, reality is wonderful,” he says. “People need to appreciate reality and not hide behind the smokescreen of superstition.”

Krauss says there’s hope, noting interest in religion is on the decline.

“More and more people are coming to realize that they can think for themselves,” says Krauss. “It’s amazing to discover that you’re wrong. In fact, it’s liberating. It’s not a threat. It opens your mind.”

The Unbelievers premieres at Hot Docs on April 29 and screens May 1 at 3:00 p.m., May 4 at 1:30 p.m. and May 5 at 1:30 p.m. Click here for more information.